1. Field of the Invention
The present invention relates generally to the recording of data to optical media, and more specifically to a method for recording data to a rewritable DVD disc having a previously written session or sessions.
2. Description of the Related Art
Currently, rewritable DVD discs provide the user with storage capacities of up to 4.3 Gigabytes on a single side. This would potentially allow users to store much more data than on conventional CD-ROMs. However, certain limitations on the current reading capability of the rewritable DVD disc does not allow the user to realize this full potential.
As is well known, there are several types of optical media standards to define structure and format on optical media to ensure compatibility across disparate operating systems, components, and devices. One standard that covers rewritable DVD discs is UDF (Universal Disc Format). UDF Revision 1.02 applies to rewritable DVD discs that have data and video capability. However, working with the UDF Revision 1.02 has limitations.
During the operation of reading data from the rewritable DVD disc, the following steps occur. When the DVD is first read the session is searched for a file system. The file system contains an anchor. The anchor contains pointers. Each pointer acts like a map and points to the location of the files or data, which have been stored on the disc. The problem is that when the disc is read it will always go to the file system associated with a first recorded session. Once a first session is closed, the file system is no longer updated. So even if data is appended after the first session the first file system's anchor pointers will only point to the data files of the first session.
For example, the user could write a small 200 Megabyte file in a first session and then will not be able to store subsequent files due to the limitations discussed above. This would leave the remaining more than 4 Gigabytes as wasted space. As can be appreciated, this drawback defeats one of the main purposes of the innovation of DVD technology, which is increased storage capacity.
In view of the foregoing, what is needed is a method and system for enabling the recording of multiple sessions onto a rewritable DVD disc, and allowing the later reading of data stored in all recorded sessions.